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Abstract:

The invention relates to a rotation device, such as a pump or a
hydromotor of the rotating type, wherein a rotation-symmetrical rotor
bounds at least two rotor channels together with radial baffles. The
rotor comprises two generally goblet-shaped dishes, the innermost dish of
which is stiffened by a first stiffening plate which has a peripheral
widening, for instance branches in its peripheral zone into at least two
rings which are rigidly connected with at least two respective bent
peripheral edges, substantially over the whole outer surfaces thereof, to
the inner surface of the peripheral edge of the relevant dish such that
the stiffness of the peripheral edge of the dish is increased.

Claims:

1-24. (canceled)

25. A rotation device, comprising: (a) a housing with a central,
substantially axial first medium passage and at least one substantially
axial second medium passage; (b) a rotor shaft which extends in the
housing and outside the housing and which is rotatably mounted relative
to the housing and supports a rotor accommodated in the housing, which
rotor branches with a central third medium passage into a number of
angularly equidistant rotor channels, each extending in a respectively at
least more or less flat main plane perpendicular to the rotation axis of
the rotor from the third medium passage to a respective fourth medium
passage, wherein the end zone of the third medium passage and the end
zone of the fourth medium passage each extend in an at least more or less
axial direction and each rotor channel has a curved form, and has a
middle part which extends in a direction with at least a considerable
radial component, and each rotor channel has a flow tube cross-sectional
area, which increases in the direction from the third medium passage to
the fourth medium passage from a relative value of 1 to a relative value
of at least 4; (c) a stator accommodated in the housing, comprising: a
first central body which has a substantially rotation-symmetrical, curved
or hybrid formed outer surface with a smooth form which, together with an
inner surface of the housing, bounds a generally substantially
rotation-symmetrical medium passage space with a radial dimension of a
maximum of 0.4 times the radius of said outer surface, in which medium
passage space are accommodated a number of angularly equidistant stator
baffles which in pairs bound stator channels, and each stator baffle has
at a first end zone directed toward the rotor and forming a fifth medium
passage a direction varying substantially from the axial direction, and
at a second end zone forming a sixth medium passage a direction varying
little, from the axial direction, which fifth medium passages connect for
medium flow in a substantially axial direction to the fourth medium
passages and are placed at substantially the same radial positions, and
which sixth medium passages are connected to the at least one second
medium passage; a second central body connecting to the first central
body, wherein between the sixth medium passage and the at least one
second medium passage there extends at least one manifold channel
extending in the direction from the sixth medium passages to the at least
one second medium passage and bounded by the outer surface of the second
central body and the inner surface of the housing; wherein a general
medium throughflow path is defined between the first medium passage and
the at least one second medium passage through respectively the first
medium passage, the third medium passages, the rotor channels, the fourth
medium passages, the stator channels, the sixth medium passages, the at
least one manifold channel, the at least one second medium passage, and
vice versa, with substantially smooth and continuous transitions between
said parts during operation; wherein the structure is such that during
operation there is a mutual force coupling between the rotation of the
rotor, and thus the rotation of the shaft, on the one hand and the
pressure in the medium flowing through said medium throughflow path;
wherein the rotor comprises two rotation-symmetrical dishes, a first dish
adjoining the first medium passage and a second dish disposed at a
position remote from the first medium passage, wherein the two dishes,
together with baffles also serving as spacers, bound the rotor channels,
the axes of said dishes coinciding with the rotation axis of the rotor;
wherein the dishes and the baffles consist of sheet material; and wherein
the second dish is stiffened by stiffening means which comprise: a first
stiffening plate extending in a plane perpendicular to the axis of the
rotor, which stiffening plate is connected in a tensively strong manner
on one side to the rotor shaft and on the other side to the outer
peripheral edge of the second dish extending in at least a more or less
axial direction; and a shoring structure connected on one side to the
rotor shaft and on the other to a middle part of the second dish, this
middle part extending with at least a considerable radial component;
wherein, the first stiffening plate in its peripheral edge zone has an
annular widening, of which the outer surface located radially furthest
outward is connected rigidly to the inner surface of the second dish such
that the stiffness of the peripheral edge of the dish is increased.

26. The device as claimed in claim 25, wherein the first stiffening plate
branches in its peripheral edge zone into at least two rings which, with
at least two respective bent peripheral edges substantially over the
whole outer surfaces thereof, are rigidly connected to the inner surface
of the peripheral edge of the second dish.

27. The device as claimed in claim 26, wherein the peripheral edges of
the least two rings at least substantially connect to each other.

28. The device as claimed in claim 25, wherein the shoring structure
comprises: a second stiffening plate extending in a plane perpendicular
to the axis of the rotor, wherein the second stiffening plate is
connected in a tensively strong manner on one side to the rotor shaft and
on the other side to the middle part, extending with a considerable
radial component, of the second dish.

29. The device as claimed in claim 25, wherein the shoring structure
comprises: a substantially truncated conical dish which is connected in a
tensively strong manner on one side to the rotor shaft and on the other
side to the middle part of the second dish, and extends from an inner
zone of the first stiffening plate, and is connected rigidly with a bent
peripheral edge to an inner surface of the middle part of the second dish
over substantially the whole surface of this peripheral edge.

30. The device as claimed in claim 29, wherein the attachment of a second
stiffening plate and the peripheral edge of the truncated conical
stiffening dish are mutually adjacent in the region of the middle part of
the second dish.

31. The device as claimed in claim 28, wherein the first stiffening
plate, the second stiffening plate, the truncated conical dish, or any
combination thereof is clamped with a central zone between two clamping
rings coupled to the rotor shaft.

32. The device as claimed in claim 31, wherein the clamping rings have a
radially outward narrowing form, in the manner of a Laval construction.

33. The device as claimed in claim 32, wherein the first stiffening
plate, the second stiffening plate, or both are clamped between the
clamping rings via round discs which are situated on both sides of the
stiffening plate and which have a greater diameter than the clamping
jaws, in the manner of a Laval construction.

34. The device as claimed in claim 31, wherein the first stiffening
plate, the second stiffening plate, or both are clamped via a truncated
conical inner zone between two correspondingly formed annular clamping
surfaces of the clamping rings.

35. The device as claimed in claim 34, wherein an annular zone at the
position of the transition between a flat part of the clamping surface
and a truncated conical part of the clamping surface having an angle
between 90.degree. and 180.degree. is provided with an annular recess.

36. The device as claimed in claim 26, wherein one ring forms part of a
first plate; a further ring forms part of or is connected to at least one
second plate; and the first and the at least one second plate are
disposed together as a package.

37. The device as claimed in claim 26, wherein the rings are formed,
placed and connected to the peripheral edge of the second dish such that
the centrifugal forces occurring during rotation of the rotor are not
sufficient to elastically deform the curved peripheral edge of the second
dish to any substantial extent.

38. The device as claimed in claim 31, wherein the clamping rings are
pressed with force toward each other by means of a screw connection
coaxial to the rotation axis of the rotor.

40. The device as claimed in claim 28, wherein each dish or each dish
part, optionally together with the second stiffening plate, is
manufactured by deep-drawing.

41. The device as claimed in claim 28, wherein each dish or each dish
part, optionally together with the second stiffening plate, is
manufactured by successively performing the following steps of (a)
providing a plate of metal with the form of a flat ring from which is
missing a segment bounded by two complementary edges extending in radial
direction; (b) welding these two edges to each other such that a
truncated cone of sheet metal is created, the half-apex angle of which is
roughly equal to the angle of inclination of the dish or the dish part in
the region around the half radius of the dish; (c) providing a mould, of
which the complementary mould parts to be urged with force toward each
other each have a form roughly corresponding to the desired form of the
dish or the dish part; (d) placing the truncated cone in the opened
mould; (e) pressing the mould parts with force toward each other with
elastic and plastic deformation of the truncated cone such that a dish or
dish part, optionally together with a second stiffening plate, is
obtained of the desired form; (f) opening the mould; and (g) removing the
obtained dish or the dish part, optionally together with the second
stiffening plate.

42. The device as claimed in claim 40, wherein each dish consists of two
parts, a middle part and a peripheral part connected thereto via a
circular join.

43. The device as claimed in claim 42, wherein the peripheral part is
formed integrally with the second stiffening plate and the join is
situated in a transition zone between the peripheral part and the second
stiffening plate.

44. The device as claimed in claim 25, wherein the dishes are formed from
metal by deep-drawing, rolling, forcing, hydroforming, explosive
deformation, by means of a rubber press, machining, casting, injection
moulding, or a combination of at least two thereof.

45. The device as claimed in claim 25, wherein the dishes are formed from
plastic by injection moulding, thermoforming, or thermovacuum-forming
which plastic can optionally be reinforced with tensively strong fibres.

46. The device as claimed in claim 25, wherein the dishes are
manufactured from sheet-metal which is laid in at least two layers one
over the other in a mould with a mould cavity having a form corresponding
to the desired form of the rotor, between which two layers medium under
pressure is admitted to cause expanding of the sheet material during
plastic deformation against the wall of said mould cavity for forming of
the rotor.

47. A device as claimed in claim 25, which rotation device is embodied as
pump, and the rotor has in the region of the first medium passage an
infeed propeller or inducer which comprises a number of double-curved
blades.

48. A device as claimed in claim 25, wherein the device is embodied as
pump, and wherein the rotor comprises at least two pairs of goblet-shaped
dishes placed in nested relation, each of which dishes is connected in a
tensively strong and stiff manner to an adjacent dish.

Description:

[0001] The invention relates to a rotation device, such as a pump, a
turbine or a hydromotor, comprising:

[0002] (a) a housing with a central, substantially axial first medium
passage and at least one substantially axial second medium passage;

[0003] (b) a rotor shaft which extends in this housing and outside this
housing and which is rotatably mounted relative to this housing and
supports a rotor accommodated in this housing, which rotor branches with
a central third medium passage into a number of angularly equidistant
rotor channels, each extending in a respectively at least more or less
flat main plane perpendicularly of the rotation axis of the rotor from
the third medium passage to a respective fourth medium passage, wherein
the end zone of the third medium passage and the end zone of the fourth
medium passage each extend in at least more or less axial direction and
each rotor channel has a curved form, for instance a general U-shape or a
general S-shape, has a middle part which extends in a direction with at
least a considerable radial component, and each rotor channel has a flow
tube cross-sectional area, i.e. a section transversely of each local main
direction, which increases in the direction from the third medium passage
to the fourth medium passage from a relative value of 1 to a relative
value of at least 4;

[0004] (c) a stator accommodated in this housing, comprising:

[0005] (c.1) a first central body which has a substantially
rotation-symmetrical, for instance at least more or less cylindrical, at
least more or less conical, curved or hybrid formed outer surface with a
smooth form which, together with an inner surface of the housing, bounds
a generally substantially rotation-symmetrical, for instance cylindrical
medium passage space with a radial dimension of a maximum of 0.4 times
the radius of said outer surface, in which medium passage space are
accommodated a number of angularly equidistant stator baffles which in
pairs bound stator channels, which stator baffles each have at their end
zone directed toward the rotor and forming a fifth medium passage (24) a
direction varying substantially, in particular at least 60°, from
the axial direction, and at their other end zone forming a sixth medium
passage a direction varying little, in particular by a maximum of
15°, from the axial direction, which fifth medium passages connect
for medium flow in substantially axial direction to the fourth medium
passages and are placed at substantially the same radial positions, and
which sixth medium passages are connected to the at least one second
medium passage;

[0006] (c.2) a second central body connecting to the first central body,
wherein between the sixth medium passage and the at least one second
medium passage there extends at least one manifold channel extending in
the direction from the sixth medium passages to the at least one second
medium passage and bounded by the outer surface of the second central
body (23) and the cylindrical inner surface of the housing;

[0007] wherein a general medium throughflow path is defined between the
first medium passage and the at least one second medium passage through
respectively the first medium passage, the third medium passages, the
rotor channels, the fourth medium passages, the stator channels, the
sixth medium passages, the or each manifold channel, the second medium
passages, and vice versa, with substantially smooth and continuous
transitions between said parts during operation;

[0008] wherein the structure is such that during operation there is a
mutual force coupling between the rotation of the rotor, and thus the
rotation of the shaft, on the one hand and the pressure in the medium
flowing through said medium throughflow path;

[0009] wherein the rotor comprises two rotation-symmetrical, generally
goblet-shaped dishes, i.e. a first dish adjoining the first medium
passage, and a second dish disposed at a position remote from the first
medium passage, which two dishes, together with baffles also serving as
spacers, bound the rotor channels, the axes of said dishes coinciding
with the rotation axis of the rotor;

[0010] wherein the dishes and the baffles consist of sheet material, for
instance optionally fibre-reinforced plastic, an aluminium (alloy), a
titanium (alloy), stainless steel or spring steel; and

[0011] wherein the second dish is stiffened by stiffening means which
comprise: [0012] a first stiffening plate extending in a plane
perpendicularly of the axis of the rotor, which stiffening plate is
connected in tensively strong manner on one side to the rotor shaft and
on the other side to the outer peripheral edge of the second dish
extending in at least more or less axial direction; and [0013] a shoring
structure connected on one side to the rotor shaft and on the other to
the middle part of the second dish, this middle part extending with at
least a considerable radial component.

[0014] Such a rotation device is known from NL-C-1009759 and the Europe
patent application EP-A-1 102 936 based thereon.

[0015] The known device is found to have the problem at the mechanically
realizable very high rotation speeds that the roughly goblet-shaped rotor
dishes display, as a result of the very high centrifugal forces which
occur, a radial and an axial deformation, particularly at their free
peripheral edges, such that this can have an adverse effect on the
operation of the rotation device. For instance when operating as pump,
wherein the rotor is driven by a motor, the free end edges of the dishes
must extend some distance inside the annular inlet space of the stator.
As a consequence of the described elastic deformation at extremely high
rotation speeds there is the risk of the rotor end edges coming into
contact with the stator. This cannot be permitted and therefore imposes a
limit on the maximum achievable rotation speed. The rotation speed can
nevertheless be increased for mechanical reasons because the materials
applied, in particular suitable types of metal, can be loaded to higher
rotation speeds and corresponding speeds of revolution without exceeding
their elastic limit.

[0016] It is for this reason that the invention has for its object to
embody a device of the known type such that at the highest achievable
rotation speed to be determined on materials science basis the radial
displacement of the end edges of the dishes lies within a predetermined
tolerance value, in accordance with a maximum allowable elastic
deformation, corresponding to the distance between the peripheral edge of
the relevant outer rotor dish and, located some distance outside it, the
part of the relevant outer inlet wall of the stator.

[0017] On the basis of these considerations, the invention provides a
rotation device of the described type which has the feature that the
first stiffening plate has in its peripheral edge zone an annular
widening, of which the outer surface located radially furthest outward is
connected rigidly to the inner surface of the second dish such that the
stiffness of the peripheral edge of the dish is increased.

[0018] This rotation device can for instance have the special feature that
the first stiffening plate branches in its peripheral edge zone into at
least two rings which, with at least two respective bent peripheral edges
substantially over the whole outer surfaces thereof, are rigidly
connected to the inner surface of the peripheral edge of the second dish.

[0019] It is noted here that from said publication NL-C-1009759, in
particular FIG. 2 thereof, a rotation device with a rotor is known, the
inner dish of which is stiffened with a stiffening plate and a number of
truncated conical shores. The stiffening plate extends from the shaft of
the rotor and is connected to the associated dish.

[0020] The shores have a generally zigzag structure in the form of
rotation-symmetrical plates, so in the manner of truncated cone shapes,
present between stiffening plate and the dish and connected thereto.
Mention is made of the use of metal, for instance stainless steel or
spring steel.

[0021] Despite this apparently very rigid construction, this prior art
rotor structure is found not to meet the extreme demands to be made
according to the invention of the freedom from elastic deformation of the
rotor. It is found particularly that, while a radial stiffening has
certainly occurred, the centrifugal forces result in the occurrence of a
bending moment, as a result of which the end edge in question moves away
from the stator inlet, with the subsequent result that a radial
deformation component also occurs. As a result of this structure the
desired extremely high rotation speed is found not to be realizable with
the known structure.

[0022] The invention is based on the insight that it is essential not only
to strengthen the peripheral edge of the inner dish in radial direction
but also to increase the stiffness, in particular the bending stiffness,
of the peripheral edge of the dish. This wish is now realized with the
described structure according to the invention, wherein use is made of
two, three or even more rings which are connected in tensively strong
manner to the inner zone of the first stiffening plate, and the
peripheral edges of which are bent through an angle corresponding to the
local angle of inclination of the peripheral edge. In this way a very
light, low-deformation and particularly stiff structure is obtained by
means of welding, in particular spot-welding. It must be seen as very
important here that at the "forking point", so the zone where the rings
come together, therefore at a position lying radially closer to the rotor
axis, the relevant zone is substantially only under strain of tension,
wherein it is necessary to avoid as far as possible the zone also being
under strain of bending.

[0023] When for instance three rings are used, the middle ring can extend
exactly in transverse direction relative to the rotor axis, while the
other two rings, which have a truncated conical form, are dimensioned
such that the stated criterion is met. This has been found in practice to
result in such an improvement in the technical properties of the rotor
that even the extremely high rotation speeds achievable on materials
science basis can be realized. As a result the rotation device according
to the invention can be utilized over a substantially greater range of
rotation speeds than the known rotation device.

[0024] According to an important aspect of the invention, the device has
the special feature that the peripheral edges of the least two rings at
least substantially connect to each other. This achieves that the
peripheral edges together form a more or less continuous annular
stiffening and strengthening ring, and together make a further
contribution toward stiffening the peripheral edge of the relevant dish.

[0025] It has been found that, even with the above described structure
according to the invention, there is still the risk of the goblet-shaped
dish undergoing a certain, albeit small, elastic deformation. This
deformation occurs roughly in the middle, or the annular inflection point
zone of the goblet-shaped dish. This deformation, which has an axial and
bending component as well as a radial one, can be almost wholly prevented
with a structure in which the shoring structure comprises:

[0026] a second stiffening plate extending in a plane perpendicularly of
the axis of the rotor, which second stiffening plate is connected in
tensively strong manner on one side to the rotor shaft and on the other
side to the middle zone, extending with a considerable radial component,
of the second dish.

[0027] An even greater improvement is realized with an embodiment in which
the shoring structure comprises:

[0028] a substantially truncated conical dish which is connected in
tensively strong manner on one side to the rotor shaft and on the other
side to the middle zone of the second dish, and extends from the inner
zone of the first stiffening plate, and is connected rigidly with a bent
peripheral edge to the inner surface of the middle zone of the second
dish over substantially the whole surface of this peripheral edge.

[0029] Based on the same considerations as above given in respect of the
peripheral edges of the rings, the device can advantageously further have
the special feature that the attachment of the second stiffening plate
and the peripheral edge of the truncated conical stiffening dish are
mutually adjacent in the region of the middle zone of the second dish.

[0030] In the known rotation device according to NL-C-1009759 the manner
in which the stiffening structures are coupled to the shaft is left
unclear. In respect of the very great radial forces which occur, so
tensile forces, it can be deemed essential that the tensile strength of
the connection between the rotor shaft and the stiffening structure as
well as the shoring structure meets very high mechanical standards of
resistance to tensile strain, strength and non-deformability.

[0031] Is also important that the rotor is designed such that it can be
produced in relatively simple manner, wherein the production tolerances
are extremely low, so that it is even possible to dispense with a
finishing process, in particular a balancing process.

[0032] In this respect the device can have the special feature that the
first and/or the second stiffening plate and/or the truncated conical
dish is clamped with a central zone between two clamping rings coupled to
the rotor shaft.

[0033] Particularly favourable in respect of a very high mechanical
strength and lack of deformability on the one hand and a low mass inertia
and mass on the other is an embodiment in which the clamping rings have a
radially outward narrowing form, in the manner of a Laval construction.

[0034] A Laval construction is a model of an optimal rotor developed on a
theoretical basis, wherein the material of a more or less disc-like
rotating structure is under roughly the same strain of tension at any
radial position. Such a structure can be theoretically calculated and is
found to have an increasing axial dimension in the region of the central
axis, this dimension becoming smaller as the radial distance from the
axis increases. Use can fruitfully be made of this insight in the
invention in order to obtain a low mass inertia and a low mass.

[0035] Use can also be made of this insight in a further development,
wherein the stiffening plate is clamped between the clamping rings via
round discs which are situated on both sides of the stiffening plate and
which have a greater diameter than the clamping jaws, in the manner of a
Laval construction.

[0036] An extremely low dimensional tolerance and freedom from deformation
can be guaranteed with an embodiment in which the first and/or the second
stiffening plate are clamped via a truncated conical inner zone between
two correspondingly formed annular clamping surfaces of the clamping
rings.

[0037] In a specific embodiment hereof the device can have the special
feature that the annular zone at the position of the transition between
the flat part of a clamping surface and the truncated conical part of
this clamping surface and having an angle between 90° and
180° is provided with an annular recess. Protruding clamped plate
material can be received herein such that the clamping force of the
mutually facing clamping surfaces is not concentrated in this protruding
material, but is distributed as well as possible over the whole surface,
whereby the pressure remains controllable and limited.

[0038] The first plates together form a structure which can be implemented
in different ways.

[0039] The device can for instance have the special feature that one ring
forms part of a first plate;

[0040] a further ring forms part of or is connected to a second plate; and

[0041] the first and the at least one second plate are disposed together
as package.

[0042] According to yet another aspect of the invention, in accordance
with those discussed above, the device can have the special feature that
the rings are formed, placed and connected to the peripheral edge of the
second dish such that the centrifugal forces occurring during rotation of
the rotor are not sufficient to elastically deform the curved peripheral
edge of the second dish to any substantial extent.

[0043] A very practical production method can be realized with an
embodiment in which the clamping rings are pressed with force toward each
other by means of a screw connection coaxial to the rotation axis of the
rotor.

[0044] This latter embodiment can for instance have the special feature
that the screw connection comprises two co-acting conical screw threads.

[0045] Co-acting conical screw threads are per se known. Provided they are
well designed, they have good properties and have the great advantage of
having an inherent locating function, rapidly and without erroneous
positioning, whereby the two screw threads can be coupled to each other
with a simple turn. It is found in practice that an adequate coupling is
realized when the screw threads are rotated for instance through an angle
in the order of 180° relative to each other. As a consequence of
the single rotation direction of the rotation device according to the
invention the screw connection will tighten itself during operation of
the device, while the screw connection can nevertheless easily be
released, for instance for maintenance or repair, by exerting a rotation
force directed counter to this rotation direction.

[0046] According to a specific aspect of the invention, the device has the
special feature that each dish or each dish part, optionally together
with the second stiffening plate, is manufactured by deep-drawing.

[0047] It is noted here that deep-drawing in one deep-drawing operation is
not always possible. A deep-drawing process is limited by the geometry
and the material properties of the starting sheet. In some circumstances
multiple successive deep-drawing operations are required so that the
final form is achieved in stages. It is possible to obviate this drawback
to at least some extent by constructing a dish from more than one, for
instance two or three, dish parts which can be attached to each other
with annular zones, for instance by welding, in particular spot-welding.
These dish parts can often be manufactured in one deep-drawing operation.

[0048] According to another aspect of the invention, the device can have
the special feature that

[0049] each dish or each dish part, optionally together with the second
stiffening plate, is manufactured by successively performing the
following steps of:

[0050] (a) providing a plate of metal with the form of a flat ring from
which is missing a segment bounded by two complementary, for instance
straight edges extending in radial direction;

[0051] (b) welding these two edges to each other such that a truncated
cone of sheet metal is created, the half-apex angle of which is roughly
equal to the angle of inclination of the dish or the dish part in the
region around the half radius of the dish;

[0052] (c) providing a mould, of which the complementary mould parts to be
urged with force toward each other each have a form roughly corresponding
to the desired form of the dish or the dish part;

[0053] (d) placing the truncated cone in the opened mould;

[0054] (e) pressing the mould parts with force toward each other with
elastic and plastic deformation of the truncated cone such that a dish or
dish part, optionally together with a second stiffening plate, is
obtained of the desired form;

[0055] (f) opening the mould; and

[0056] (g) removing the obtained dish or the dish part, optionally
together with the second stiffening plate.

[0057] The above described process can be referred to as
"stretch-pressing".

[0058] As already discussed briefly above, in the above described two
exemplary embodiments of the invention the device can have the special
feature that each dish consists of two parts, i.e. a middle part and a
peripheral part connected thereto via a circular join.

[0059] Further discussed is a variant in which the shoring structure has a
second stiffening plate. Such a device can be combined with the device
according to the previous paragraph, wherein the peripheral part is
formed integrally with the second stiffening plate and the join is
situated in the transition zone between the peripheral part and the
second stiffening plate.

[0060] A device according to the invention can in general have the special
feature that the dishes are formed from metal by deep-drawing, rolling,
forcing, hydroforming, explosive deformation, by means of a rubber press,
machining, casting, injection moulding, or a combination of at least two
thereof.

[0061] In yet another embodiment the device has the special feature that
the dishes are formed from plastic by injection moulding, thermoforming,
thermovacuum-forming or the like, which plastic can optionally be
reinforced with tensively strong fibres, or for instance glass fibres.

[0062] Finally, the invention can have the special feature that a dish is
manufactured from sheet-metal which is laid in at least two layers one
over the other in a mould with a mould cavity having a form corresponding
to the desired form of the rotor, between which two layers medium under
pressure is admitted to cause expanding of the sheet material during
plastic deformation against the wall of said mould cavity for forming of
the rotor.

[0063] The use of sheet material for manufacturing the dishes and the
baffles has the advantage that the rotor can be very light. Sheet
material can further be very light, smooth and dimensionally accurate.
The choice of the material will be further determined by considerations
of wear-resistance (depending on the passing medium), bending stiffness,
mechanical strength and the like. For the rotor, the dishes of which have
the described double-curved, general goblet shape, it is important that
the main shape is retained even if the material is subjected to
centrifugal forces as a result of high rotation speeds. Attention is
drawn in this respect to the fact that the baffles arranged between the
dishes and rigidly coupled thereto make a considerable contribution
toward the stiffening of the rotor. It is also important for this reason
to use a large number of baffles. A rotor can also be manufactured of
very high dimensional accuracy and negligible intrinsic imbalance.

[0064] Small wall thicknesses make manufacture possible with deep-drawing.

[0065] It would also be possible to work on the basis of a machining
process, for instance milling or spark machining. A rough form can also
be realized beforehand with a suitable process, for instance by injection
moulding of an aluminium, after which the final form is realized with a
finishing process, for instance a machining process, such as milling,
spark machining, grinding, polishing.

[0066] The invention will now be elucidated on the basis of the
accompanying drawings. In the drawings:

[0067] FIG. 1 shows partially in cross-section, partially in cut-away side
view a first exemplary embodiment of a rotation device according to
NL-C-1009759;

[0068] FIG. 2 shows a partially cut-away perspective view of a second
exemplary embodiment of a rotation device according to NL-C-1009759; and

[0069] FIG. 3 shows a perspective exploded view from the underside of a
rotor according to NL-C-1009759;

[0070] FIG. 4 is a longitudinal section of a rotation device according to
the invention, wherein the structure is of a two-stage type, wherein two
medium throughflow circuits are connected in cascade with each other,
whereby for instance a pump can realize a substantially higher pressure
increase;

[0071] FIG. 5A shows the rotor of the device according to FIG. 4;

[0072] FIG. 5B shows a longitudinal section corresponding to FIG. 5A of
another embodiment of the rotor;

[0073] FIG. 6A shows on enlarged scale a part of a rotor according to FIG.
5 in a first embodiment;

[0074] FIG. 6B shows a longitudinal section corresponding to FIG. 6A of a
part of a rotor in a second embodiment;

[0075] FIG. 6C shows a longitudinal section corresponding to FIG. 6B of a
part of a rotor in a further embodiment as according to FIG. 5B;

[0076] FIG. 7A shows a metal blank;

[0077] FIG. 7B shows a truncated cone form realized on the basis of the
blank of FIG. 7A;

[0078] FIG. 8A shows a longitudinal section through a mould having the
truncated cone of FIG. 7B therein for the purpose of forming a dish of a
rotor according to the invention;

[0079] FIG. 8B shows a dish realized with the mould according to FIG. 8A;

[0080] FIG. 9A shows an exploded view of the rotor according to FIG. 6A,
wherein the components are drawn in longitudinal section and several
components, in particular a number of rotor baffles, are omitted for the
sake of clarity;

[0081] FIG. 9B shows an exploded view corresponding to FIG. 9A of the
rotor according to FIG. 6B;

[0082] FIG. 9C shows an exploded view corresponding to FIGS. 9A and 9B of
the rotor according to FIGS. 5B and 6C;

[0083] FIG. 10 shows a longitudinal half-section through a pump with a
rotor according to the invention;

[0084] FIG. 11 shows on enlarged scale the detail XI of a dish of the
rotor of FIG. 10;

[0087] FIG. 14 shows a blank for manufacturing a combination of two inlet
blades;

[0088] FIG. 15 is a perspective view of the unit of two blades after
performing of a modelling process;

[0089] FIG. 16 is a perspective view at an angle from below of an infeed
propellor comprising three pairs of blades as according to FIG. 15;

[0090] FIG. 17 is a cut-away partial view of a quarter of a rotor in yet
another embodiment, wherein the greater part of the inner dish is not
shown and the core is not shown, such that the placing of the baffles is
clearly visible;

[0091] FIG. 18 shows a detail of a strengthening and mounting ring with
groove at the position of the baffles;

[0092] FIG. 18A shows the view A of FIG. 18, i.e. the blade in the ring;

[0093] FIG. 18B shows the section B-B, i.e. the placing of the baffles in
the recess of the ring;

[0094] FIG. 19 shows a detail of the possible placing of baffles which,
for the purpose of a good rotor balance, are placed in alternating
orientation;

[0095] FIG. 20 shows a view corresponding to FIG. 19 of a variant wherein
the baffles are placed back-to-back;

[0096] FIG. 21 shows a view corresponding to FIGS. 19 and 20 of an
embodiment wherein the baffles have a slightly oblique position relative
to the radial line;

[0097] FIG. 22 shows a view corresponding to FIGS. 19, 20 and 21 of an
embodiment in which the baffles are enclosed at their end zones and are
welded fixedly between prearranged threads;

[0098] FIG. 23 shows a longitudinal section through a half-rotor with a
structure corresponding to that of FIG. 17, but wherein the Laval
stiffening construction is constructed in a different manner;

[0099] FIG. 24 is a schematic side view of a welding device for welding
the blades of figure is 25A and 25B to the inner dish;

[0100] FIG. 25A is a side view of a blade in a further embodiment;

[0101] FIG. 25B is a top view of the blade of FIG. 25A;

[0102] FIG. 26 shows a view corresponding to FIGS. 19, 20, 21 and 22 of a
preferred embodiment of the blades after fixation between the dishes of
the rotor according to FIGS. 25A and 25B.

[0103] FIG. 1 shows a rotation device 1. This comprises a housing 2 with a
central axial first medium passage 3 and three axial second medium
passages 4, 5, 6. Device 1 further comprises a shaft 7 which extends in
said housing 2 and outside this housing 2 and which is rotatably mounted
relative to housing 2, by means of among others a bearing 247, and
supports a rotor 8, which will be specified below, accommodated in
housing 2. Rotor 8 connects with a central third medium passage 9 to
first medium passage 3. Third medium passage 3 branches into a number of
angularly equidistant rotor channels 10, each extending in a respectively
at least more or less radial main plane from third medium passage 9 to a
respective fourth medium passage 11. The end zone of third medium passage
9 and the end zone of fourth medium passage 11 each extend in
substantially axial direction. As shown in FIG. 1, each rotor channel 10
has a generally slight S-shape, roughly corresponding to a half-cosine
function, and has a middle part 12 which extends in a direction having at
least a considerable radial component. Each rotor channel has a
cross-sectional surface area which increases from the third medium
passage to the fourth medium passage.

[0104] Rotation device 1 further comprises a stator 13 accommodated in
housing 2. This stator 13 comprises a first central body 14 and a second
central body 23.

[0105] The first central body 14 has on its zone adjoining rotor 8 a
cylindrical outer surface 15 which, together with a cylindrical inner
surface 16 of housing 2, bounds a generally cylindrical medium passage
space 17 with a radial dimension of a maximum of 0.2 times the radius of
the cylindrical outer surface 15, in which medium passage space 17 are
accommodated a number of angularly equidistant stator blades 19 which in
pairs bound stator channels 18, and which stator blades 19 each have, on
their end zone 20 directed toward rotor 8 and forming a fifth medium
passage 24, a direction differing substantially, in particular at least
60°, from the axial direction 21, and on their other end zone 22
forming a sixth medium passage 25 a direction differing little, in
particular a maximum of 15°, from the axial direction 21, which
fifth medium passages 24 connect to the fourth medium passages 11 and
which sixth medium passages 25 connect to the three second medium
passages 4, 5, 6.

[0106] The second central body is embodied such that between the sixth
medium passage 25 and the second medium passages 4, 5, 6 three manifold
channels 26 extend tapering in the direction from the sixth medium
passages 25 to the second medium passages 4, 5, 6. These manifold
channels are also bounded by the outer surface 29 of the second central
body 23 and the cylindrical inner surface 16 of housing 2.

[0107] FIG. 1 indicates with arrows a general medium throughflow path 27.
This path 27 is defined between the first medium passage 3 and the second
medium passages 4, 5, 6 through respectively: first medium passage 3,
third medium passages 9, rotor channels 10, fourth medium passages 11,
stator channels 18, sixth medium passages 25, manifold channels 26,
second medium passages 4, 5, 6, with substantially smooth transitions
between said parts. It is noted that in FIG. 1 the flow of the medium
according to arrows 26 is shown in accordance with a pumping action of
device 1, for which purpose the shaft 7 is driven rotatingly by motor
means (not shown). If medium under pressure were to be admitted with
force via medium passages 4, 5, 6 into the second medium passages 4, 5,
6, the medium flow would then be reversed and the rotor 8 would be driven
rotatingly, also while driving shaft 7 rotatably, due to the structure of
device 1 to be described hereinbelow.

[0108] The structure of the device is such that during operation there is
a mutual force coupling between the rotation of rotor 8, and thus the
rotation of the shaft, on the one hand and the speed and pressure in the
medium flowing through said medium throughflow path 27.

[0109] The device can therefore generally operate as pump, in which case
shaft 7 is driven and the medium is pumped as according to arrows 27, or
as turbine/motor, in which case the medium flow is reversed and the
medium provides the driving force.

[0112] As can be seen more clearly in FIG. 2 than in FIG. 1, an infeed
propellor 32 with a number of propellor blades 33 is arranged in the
third medium passage 9 serving as medium inlet.

[0113] Rotor 34 in device 31 according to FIG. 2 has a number of
additional strengthening shores 35 which are absent in rotor 8.

[0114] As shown in FIG. 3, rotor 8 comprises a number of separate
components which are mutually integrated in the manner to be described
below. Rotor 8 comprises a lower dish 36, an upper dish 37, twelve
relatively long baffles 38 and twelve relatively short baffles 39 placed
interwoven therewith, which in the manner shown form equidistant
boundaries of respective rotor channels 10. Baffles 38, 39 each have a
curved form and edges 40, 41 bent at right angles for medium-tight
coupling to dishes 36, 37. Baffles 38, 39 are preferably connected to the
dishes by welding, in particular spot-welding, and thus form an
integrated rotor. In the central third medium passage 9 is placed infeed
propellor 32. This has twelve blades which connect to the long rotor
baffles 38 without a rheologically appreciable transition. A downward
tapering streamlining element 42 is placed in the middle of infeed
propellor 32.

[0115] FIG. 2 shows the operation of the device 31 operating for instance
as liquid pump. By driving shaft 7 with co-displacing of rotor 34 liquid
is pressed into rotor channels 10 through the action of propellor 32.
Partly as a result of the centrifugal acceleration which occurs, a strong
pumping action is obtained which is comparable to that of centrifugal
pumps. However, centrifugal pumps operate with fundamentally differently
formed rotor channels. The liquid flowing out of rotor channels 10
displays a strong rotation and takes the form of an annular flow with a
tangential or rotation-directional component as well as an axial
directional component. Stator blades 19 remove the rotation component and
guide the initially axially introduced flow once again in axial direction
inside the manifold channels 26, where the part-flows are collected and
supplied to respective medium outlets 4, 5, 6 which join together to form
one conduit 43 so that the medium can be pumped further via one conduit.
Other embodiments are also possible, wherein the outlet also extends
almost exactly in axial direction.

[0116] FIG. 4 shows a rotation device 142 according to the invention.

[0117] In view of the description of the prior art already given as
according to FIGS. 1, 2 and 3, the description of the essential aspects
according to the invention will now suffice, in particular rotor 143.

[0118] It is noted that, other than in FIGS. 1, 2 and 3, device 142 is
constructed such that both the rotor and the stator take a dual form,
i.e. medium path 27 extends first through a first set of rotor channels,
subsequently through a first roughly cylindrical space of the stator,
then in return direction through a second cylindrical space of the
stator, then again through the rotor, though now through a second set of
rotor channels, subsequently through a third roughly cylindrical stator
space and is then discharged through the second medium passage or medium
passages. Owing to such a cascaded structure, which will be elucidated in
more detail hereinbelow with reference to the following figures, a
substantial pressure increase can be realized even in the case of gaseous
pumped media.

[0119] A parallel cascaded structure, wherein the rotor comprises two or
more pairs of goblet-shaped dishes placed in nested relation, has the
advantage of a very high degree of compactness, a low weight and a high
pressure resistance when compared to for instance a known centrifugal
pump, which comprises a number of serial cascaded stages with multiple
bearing-mounting of the shaft or shafts.

[0120] It is now already noted that the device according to the invention
can comprise more cascade stages, for instance three or even four. The
pressure increase coefficients per stage are multiplied by each other for
the purpose of gases. In a theoretical case, in which the pressure
increase per stage amounts for instance to a factor of 3 and this factor
is the same for all three cascade stages, in the theoretical case with a
threefold device according to the invention the pressure increase would
amount to a factor of 33=27. Such a pressure increase is conceivable
and actually feasible in the case of pumped gases. Such a pressure
increase cannot be realized for liquids owing to the wholly different
thermodynamic properties thereof.

[0121] In the case of gases heavier than air, such as carbon dioxide,
nitrogen and the like, a factor of 5 can for instance be realized. A
pressure increase by a factor of 10-20 can even be realized for xenon.
Such a pressure increase is important in the case of for instance carbon
dioxide, which is very useful for cooling purposes but which for this
purpose is preferably in a phase below the critical point at which the
pressure amounts to a minimum of 64 bar.

[0122] FIG. 5A shows a longitudinal section through rotor 143 which is
coupled to motor shaft 7 by means of a conical screw coupling 77.

[0124] The innermost dish 44 is connected to the adjacent dish 45 by means
of radial baffles 47 similar to baffles 38 and 39 according to FIG. 3.
The outermost dish 46 is connected to dish 45 by means of baffles 48.
Reference is also made to FIG. 9A and FIG. 9B in which (for the sake of
clarity only two) baffles 47, 48 are shown. The reader must however
picture the baffles being disposed in the manner of FIG. 3, so in
angularly equidistant manner, such that two adjacent baffles, together
with the adjoining dishes, bound the associated rotor channels.

[0125] FIG. 5A shows the manner in which only the inner dish 44 is
stiffened in accordance with the teaching of the invention.

[0126] FIGS. 5B, 6B, 6C and 9C show a rotor 201. In accordance with the
teaching of the present invention, inner dish 44 is substantially
stiffened and strengthened by a first dish structure 202 extending in
radial direction and consisting of a number of components of material
with sufficient tensile strength, for instance a high-quality type of
steel.

[0127] The form of dish structure 202 is chosen such that it complies with
the above described principles according to Laval. The dish structure
comprises a base dish 203 and a sub-dish 204 which is connected thereto
and forms a fork therewith and which is connected to base dish 203 by
means of a substantially flat spiral-shaped coupling of screw threads.

[0129] A more or less truncated conical shoring dish 208 is connected to
the inward facing part of base dish 203 via a second flat screw coupling
207 with co-acting spiral-shaped screw threads. It is rigidly connected
directly to inner dish 44. Shoring dish 208 is connected to core 210 of
the rotor via an annular hook connection 209.

[0130] The radially innermost zone 211 of the goblet-shaped dish 44 has a
flat disc-like part to which a cylindrical part connects. This form is
shown particularly clearly in FIG. 9C. The zone in question is clamped
into the upper core part 212 and the lower core part 213 of core 210.
These parts are centered exactly by means of a centering pin 214 which
fits tightly into blind holes 215, 216 in respective core parts 212 and
213.

[0131] Sub-dish 204, base dish 203, peripheral ring 206 and shoring dish
208 are connected to the goblet-shaped dish 44 by welding, in particular
spot-welding. After screw connection 205 has been effected, sub-dish 204
is welded fixedly at a number of points to the part of base dish 203
lying thereunder.

[0132] The figures show a blade 217 with flanges 218, 219. Reference is
also made in this respect to FIGS. 25A, 25B and 26.

[0133] It will be apparent that rotor 201 comprises a number of
equidistantly disposed blades 217 as according to for instance FIG. 3.

[0134] As noted, flanges 218 are connected to inner dish 44. Use is made
for this purpose of a spot-welding process.

[0135] Flanges 219 are welded in the same manner to outer dish 45.

[0136] Arranged between the end zone of flanges 219 and the outward bent
peripheral end zone 220 of outer dish 45 is a tensively strong ring 221.
This ensures a very high degree of resistance to elastic deformation of
dish 45 at high rotation speeds. This ring 221 is also fixed in place on
dish 45 and flanges 219 by spot-welding.

[0137] Inlet funnel 91 is connected to outer dish 46 by means of a third
flat screw coupling 222.

[0138] FIGS. 6A and 6B show on larger scale two different embodiments of
rotor 143, designated respectively 43a and 43b, in which the basic
principles of the invention and further elaboration thereof are
implemented in combination.

[0139] It is duly noted that, where possible and appropriate, at least
functionally corresponding elements and components are always designated
in the figures with the same reference numerals.

[0140] Peripheral edge 49 of dish 44 (44a and 44b respectively) is
stiffened by the three bent peripheral edges 50, 51, 52 of respective
rings 53, 54, 55, which form a peripheral zone of fork-like section of a
first stiffening plate 56.

[0141] Stiffening plate 56A comprises a relatively short lower disc 57, a
disc 58 lying thereabove and also forming ring 55 and having a generally
truncated conical form, a third disc 59 with a bent peripheral edge 60
which extends in substantially axial direction and to which the inner
peripheral edges 61, 62 of rings 53, 54 respectively are connected.

[0142] As shown clearly in FIGS. 6A and 6B, ring 54 extends in line with
third disc 59, therefore in radial direction.

[0143] Ring 53 has an angle of inclination in upward direction which
approximately corresponds to the angle of inclination of ring 55 in
downward direction, with the understanding that at the position of the
transition zone between third disc 59 and rings 53, 54, 55 the first
stiffening plate 56 is substantially only under strain of tension and not
under strain of bending.

[0144] Peripheral edges 50, 51, 52 substantially connect to each other and
have a form substantially corresponding to the local form of peripheral
edge 49 of dish 44.

[0145] Situated above third disc 59 is an upper disc 63 with the same
diameter as lower disc 57.

[0146] Discs 57, 56A, 59 and 63 of the package are mutually connected by
welding, in particular spot-welding. Third disc 59, ring 54 and ring 53
are mutually connected by spot-welding at the position of peripheral
edges 60, 61, 62.

[0147] The whole package 57, 56A, 59, 63 has a thickness or axial
dimension decreasing in steps as the radial distance increases. This is
in accordance with a Laval construction.

[0148] In the construction of rotor 43 this principle is also applied at a
further advanced level, i.e. the clamping between two clamping rings 64,
65 respectively, which are urged toward each other with force by means of
a conical screw connection 66. As shown clearly in FIGS. 5 and 6,
clamping rings 64 and 65 have an outward narrowing form in accordance
with the theoretical Laval structure.

[0149] The form of core 67, of which the upper clamping ring forms part,
likewise corresponds to the Laval principle, wherein the axial dimension
of the material approaches axis 21 in asymptotic manner.

[0150] The lower clamping ring 65 forms part of a separate first ring 68
which is slidable over a second ring 69 which, together with a third
clamping ring 70 of first ring 68 and a fourth clamping ring 71 forming
part of first ring 68, exerts simultaneously with first clamping ring 64
and second clamping ring 65 a clamping force on a second stiffening plate
72 which extends in radial direction and which is connected in tensively
strong manner to dish 44 in the region of a radius in the order of
magnitude of 60% of the overall dish radius. The different possible ways
of connecting the second stiffening plate 72 to dish 44a, 44b
respectively will be further discussed with reference to discussion of
the differences between rotor parts 43a and 43b according to FIGS. 6A and
6B respectively.

[0151] Situated at the position of first clamping ring 64 and second
clamping ring 65 is a radial part of a substantially truncated conical
dish 73 which is connected in tensively strong manner, on one side to
core 67 and first ring 68 and on the other to the middle zone of dish 44.
A bent peripheral edge 74 of dish 73 is connected by spot-welding to the
inner surface of the middle zone of dish 44, substantially over the whole
surface of this peripheral edge. Just as peripheral edges 50, 51, 52,
peripheral edge 74 has an angle of inclination corresponding to the local
angle of inclination of the dish.

[0152] The described sheet-form components are preferably manufactured
from an aluminium (alloy), a titanium (alloy), stainless steel or spring
steel. This makes production and assembly relatively easy and imparts
superior mechanical qualities to the rotor.

[0153] The inner dish 44 stiffened by the stiffening structures according
to the invention is connected rigidly by baffles 47, 48 to the further
dishes 45, 46 such that the overall rotor structure is stiff.

[0154] All the stated plates and dishes 72, 73, 57, 56A, 56B, 59 and 63
are provided with internal peripheral edges, which are all designated 75
for the sake of convenience and which are clamped between correspondingly
formed truncated conical surfaces of first clamping ring 64 and second
clamping ring 65. Annular recesses 75, 76 are present at the corner
points of these surfaces.

[0155] The preformed plates and dishes are thus connected in the manner
clearly shown in FIGS. 6A and 6B to core 67 with a high dimensional
stability, accuracy and tensile strength.

[0156] FIG. 5A shows that core 67 is connected to shaft 7 by means of a
second conical screw connection 77.

[0157] The structural differences between rotor component 43a according to
FIG. 6A and rotor component 43b according to FIG. 6B will now be
discussed.

[0158] In the embodiment according to FIG. 6A the dish 44a consists of two
parts, i.e. an outer dish part 78 which is formed integrally with second
stiffening plate 72 and an inner dish part 79 which is connected smoothly
thereto at the position of the transition between outer dish part 78 and
second stiffening plate 72. A welded connection can provide a
substantially seamless transition. This is important in respect of the
desired rheological properties. The outer surface of dish 44a does after
all form a boundary of the rotor channels.

[0159] Peripheral edge 74 of the truncated conical stiffening dish 73 also
engages at the position of transition zone 80.

[0160] FIG. 6B shows a structure wherein dish 44b is formed integrally and
second stiffening plate 72 is added later thereto as separate component
by means of welding.

[0161] Dish part 78, with the stiffening plate 72 formed integrally
therewith as according to FIG. 6A, has a form such it can be manufactured
by deep-drawing from a flat sheet metal disc. The same applies for inner
dish part 79.

[0162] This is not the case for dish 44b according to FIG. 6B. This dish
has a form such that it cannot be manufactured by deep-drawing.

[0163] Deep-drawing has the drawback in all circumstances that the wall
thickness of the formed component greatly depends on the local plastic
deformation. The occurrence of both stretch and compression cannot be
avoided in deep-drawing. As a result the final material properties can
generally not be well controlled. An additional drawback is that owing to
the relative inaccuracy of this process there is a high percentage of
wastage during production of technically high-grade articles, products or
components.

[0164] According to the invention use can therefore be made of another
technique.

[0165] As shown in FIGS. 7A, 7B, 8A and 8B, dish 44b as well as each dish
part 78, 72 and 79 respectively can be manufactured in another way. For
this purpose the following steps as shown schematically in the figures
are successively performed of:

[0166] (a) providing a plate 81 of metal with the form of a flat ring from
which is missing a segment 84 bounded by two radial edges 82, 83;

[0167] (b) welding these two radial edges 82, 83 to each other such that a
truncated cone 85 of sheet metal is created, the half-apex angle of which
is roughly equal to the angle of inclination of dish 44 or the dish part
in the middle region around the half radius of dish 44;

[0168] (c) providing a mould 86, of which the complementary mould parts
87, 88, 103 to be urged with force 89 toward each other each have a form
roughly corresponding to the desired form of dish 101 or the dish part;

[0169] (d) placing truncated cone 85 in the opened mould 86;

[0170] (e) pressing mould parts 87, 88, 103 with force 89 toward each
other with elastic and plastic deformation of truncated cone 85 such that
a dish 101 or dish part 78, optionally together with a second stiffening
plate 72, is obtained of the desired form;

[0171] (f) opening mould 86; and

[0172] (g) removing the obtained dish 101 or dish part 78, optionally
together with second stiffening plate 72.

[0173] Dish 101 has a bent peripheral edge 104 and two peripheral ribs,
both designated with reference numeral 102. See also FIGS. 10, 11, 12 and
13.

[0174] It is noted that edges 82, 83 need not necessarily run radially but
may also extend at another angle, and do not even necessarily have to be
straight. One condition however is that it must be possible to form a
truncated cone 85 on the basis of the blank 81 according to FIG. 7A,
wherein edges 82, 83 connect to each other in the case where the cone has
the desired form.

[0175] In FIG. 7B the welded join along which the edges 82, 83 are welded
to each other is designated with reference numeral 90.

[0176] FIGS. 9A and 9B refer to the rotor according to FIG. 5, be it in
the two embodiments according to the rotor part of respectively FIGS. 6A
and 6B.

[0177] FIG. 9A shows the manner in which the diverse components together
form rotor part 43a. Assembly of the rotor from the drawn components can
take place roughly in accordance with this exploded view, wherein the
skilled person can select the appropriate sequence for this purpose on
the basis of professional knowledge.

[0178] Shown is that the conical screw connection 66 consists of an outer
thread 66' present on core 67 and a corresponding inner thread 66''
present in core 67. In the same manner and referring to FIG. 5, there is
present on the upper side of core 67 a tapering conical thread part with
external screw thread 77' which co-acts with an internal screw thread
77'' on the end of motor shaft 7.

[0179] Infeed propellor 32 is rotatably disposed in a more or less
conically converging inlet funnel 91.

[0180] Infeed propellor 32 has six blades in the shown embodiment. The
number of blades can however also be smaller or greater, and can
particularly be in the range of 3 to 12.

[0181] Very effective operation is realized with an embodiment in which
the infeed propellor or inducer 32 has double-curved blades.

[0182] In the embodiment according to FIG. 9A intermediate dish 45 is
constructed from an outer dish part 45' and an inner dish part 45''.
These dish parts are mutually connected along a welded join.

[0183] Lower dish 46 is also assembled from two parts, i.e. an outer dish
part 46' and an inner dish part 46''. These dish parts are also mutually
connected along a welded join.

[0184] Referring to, among others, FIGS. 6A and 6B, attention is drawn to
the fact that rotor parts 43a and 43b derive their extreme mechanical
stiffness for a significant part from a number of substructures, each
having a generally triangular shape and producing the desired stiffness
in the manner of shores.

[0186] Rotor 105 comprises four dishes modelled in goblet shape, i.e. an
inner or first dish 101, a second dish 106, a third dish 107 and a fourth
dish 108. Together with second dish 106, first dish 101 bounds the rotor
channels in the first stage of the medium circuit indicated with flow
arrows 27. Third dish 107 and fourth dish 108 bound the rotor channels of
the second stage of medium path 27. In the present embodiment all dishes
are provided with two encircling stiffening ribs 102, which have the form
shown in FIG. 11, comprising a flat ring 109 and a cylindrical ring 110.
All ribs 105 have roughly the same lengthwise sectional form. So as not
to disrupt the flow pattern in medium path 27 the ribs are filled on the
side of the rotor channels with an annular mass 111 which is finished so
smoothly that it does not disturb the flow. Mass 111 consists for
instance of a cured plastic or a ceramic cement.

[0187] The space between second dish 106 and third dish 107 is filled with
a cured plastic mass 112. The described measures make an additional
contribution toward the stiffness of rotor 105.

[0188] The rotor is rotatable in practically sealing manner relative to
housing 2 and the components connected fixedly thereto. Use is made for
this purpose of labyrinth seals, all designated with reference numeral
113. Alternative rotating seals will also be discussed hereinbelow.

[0189] FIG. 12 shows an embodiment almost wholly corresponding to that of
FIGS. 10 and 11, but wherein the filling mass 112 between second dish 106
and third dish 107 is replaced by a structure wherein more or less
truncated conical rings 115 of plate material modelled by
stretch-pressing are welded fixedly to said dishes 106, 107, for instance
by spot-welding.

[0190] FIG. 13 shows a variant wherein dishes 106 and 107 are stiffened by
spirally wound threads 115, 116 respectively which are preformed in
accordance with the form of the associated dish 106, 107 and are
connected thereto by fusion welding.

[0191] FIG. 14 shows a blank 117 for manufacturing by means of a pressing
process a unit with two blades 118, 119 of an infeed propellor 120 as
drawn in FIG. 16.

[0192] FIG. 15 shows a perspective view of the form of unit 121 resulting
from modelling of blank 117 in correct manner in a mould.

[0193] FIG. 16 shows the manner in which three units 121 can be assembled
to form an infeed propellor 120.

[0194] FIG. 17 shows a cut-away view of a quarter of a rotor 122, wherein
the inner dish is partially omitted for the sake of clarity in the
drawing.

[0195] Rotor 122 according to FIG. 17 is of the single type, i.e. intended
as guide for only a single medium path 27, i.e. a non-cascaded
embodiment.

[0196] Rotor 122 comprises an inner dish 123 and an outer dish 124,
between which dishes the long baffles 38 and short baffles 39 are
sealingly disposed.

[0197] Both dishes 123, 124 have three stiffening ribs, all designated
with reference numeral 125. They are filled with a cured plastic mass or
ceramic cement 126 which protrudes to some extent in the space bounded by
dishes 123, 124. Indicated with broken lines is that baffles 38, 39 are
partially accommodated in, and thus anchored by, these plastic masses
126. It is noted that masses 126 protrude only to a limited extent in
medium path 27, and have a smooth, flowing form so that they have a
negligible effect on the medium flow.

[0198] The structure of rotor 122 is such that ribs 125 make a
considerable contribution toward the stiffness of dishes 123, 124.

[0199] FIG. 18 shows the described method of anchoring the baffles 38, 39.
In contrast to the completely flat baffles 38, 39 according to FIG. 17,
baffles 38, 39 according to FIGS. 18, 18A and 18B have bent edges 127
with which they are connected to the associated dish 123, 124, for
instance by welding, spot-welding, glueing or soldering.

[0200] The filling mass is situated between the bent edges such that the
medium channels bounded by dishes 123, 124 and baffles 38, 39 have a
substantially rectangular cross-section and the baffles are positioned
exactly within grooves cut into this filling mass 126.

[0201] FIGS. 19, 20, 21, 22 show partial end views of rotors, wherein
baffles 38, 39 are formed in different ways and attached to dishes 123,
124.

[0202] In the embodiment according to FIG. 19 baffles 38, 39 are provided
as according to the embodiment of FIG. 18B with bent edges 127 with which
they are coupled to dishes 123, 124, for instance by spot-welding. In the
embodiment of FIG. 19, in contrast to the embodiment of FIG. 19B, they
are placed in alternating orientation, i.e. pairs of corresponding edges
127 of adjacent baffles 38, 39 are directed toward each other.

[0203] FIG. 20 shows an embodiment in which baffles 38, 39 consist of two
sheet-metal strips whose whole surfaces lie against each other and which
are profiled in the manner of a sheet pile and provided with bent edges
127 such that baffles 38, 39 are connected to each of the dishes 123, 124
by means of two bent edges 127.

[0204] FIG. 21 shows an embodiment in which baffles 38, 39 have a certain
inclining position relative to the radial directions 129. Due to this
arrangement the bent edges 127 are loaded at high rotation speeds in more
uniform and balanced manner than for instance in the embodiment of FIGS.
18B and 19.

[0205] FIG. 22 shows an embodiment in which each of the baffles 38, 39 is
enclosed between, and welded to, two threads prearranged on dishes 123,
124 and all designated with reference numeral 130.

[0206] FIG. 23 shows more details of rotor 122.

[0207] Rotor 122 has a core 131 which is constructed in a manner other
than core 67 according to FIGS. 6A and 6B.

[0208] Just as rotors 43a and 43b, the structure of rotor 122 has
Laval-like forms, i.e. structures which are brought under strain of
tension by centrifugal forces and have an outward narrowing form.

[0209] Inner core 132 is connected to a disc 133 by means of corresponding
rotation-symmetrical toothings 134, 135 respectively. Inner core 132 and
disc 133 can for instance be manufactured from a suitable metal and
toothings 134 and 135 can for instance be arranged by rotary milling.

[0210] Preference is given to the use of the above described flat screw
connection. Such a screw connection can be manufactured with a more than
adequate precision. The screw coupling is effected by mutually engaging
and subsequently rotating the relevant screw threads relative to each
other through a certain angle. No form of fine balancing is necessary in
practice. When mutually engaging concentric rings are used, a production
milling machine must be able to operate with an exceptionally high
precision. It is found in practice that fine balancing of the rotor is
necessary when such a structure is used. This is the reason why
preference is given to the use of the spiral-shaped, co-acting screw
threads. These can be of a wholly flat type or also have a certain degree
of conicity on the main surfaces.

[0211] Dish 73 is coupled via a welded connection 136 to a
rotation-symmetrical first coupling part 137, while second stiffening
plate 72 forms part of a second coupling part 138. These coupling parts
137, 138 are clamped against each other by means of connections 144, 145
with annular, mutually engaging toothings, and connected to inner core
132 and an outer core 139 which is connected to inner core 132 by means
of a conical screw connection 140.

[0213] Inner core 132, disc 133, first coupling part 137, second coupling
part 138 and outer core 139 are manufactured from a suitable material, in
particular the same metal as dishes 123, 124 and baffles 38, 39.

[0214] Rings 53, 54 are connected to the relevant inner dish 123 in the
same manner as shown in FIGS. 6A and 6B.

[0215] Dish 73 is welded fixedly with its peripheral edge to inner dish
123 via a welded connection 147 with interposing of a bent peripheral
edge of second stiffening plate 72.

[0216] Attention is drawn to the fact that disc 133 and second stiffening
plate 72, as well as the outward protruding disc-like part of first
coupling part 137, have a longitudinal cross-sectional form which
complies with the theoretically ideal Laval form better than the
structures according to FIGS. 6A and 6B.

[0217] FIG. 24 shows a welding device for welding a blade 217 with flanges
218, 219 to dish 78. The welding device comprises a first electrode 223
and a second welding electrode 224. Via a connecting clamp 225 voltage is
applied to a resilient plate 226, for instance of spring steel, which is
covered on its side to be directed toward dish 78 with a plate 227 having
good electrical conductivity, for instance of copper or silver. In the
manner shown in FIG. 24 this flexible structure 226, 227 can adjust
itself to the curved form of dish 78. For this purpose plate 226 can
support with some force on support elements 228, 229.

[0218] Situated on the other side of dish 78 is the second welding
electrode 224 with an electric connecting clamp 230. Spot-welding
electrodes 231, 232 are carried by resilient strips with good electrical
conductivity 233, 234, for instance of copper. These are both
conductively connected to second connecting clamp 230. Owing to the
resilient nature of strips 233, 234, when spot-welding electrodes 231,
232 are brought to the shown position they can pass slidingly over flange
219, then take up their drawn position, in which they press with some
force on the protruding edges of flange 218, after which a welding
current can be transmitted via connecting clamps 225, 230, whereby flange
218 is welded fixedly to dish 78. This process is repeated a number of
times until the flange has been adequately welded with complete technical
certainty. The process is then performed on a following blade until all
blades have been welded in the stated manner.

[0220] FIG. 25B shows that blade 217 with flanges 218, 219 has an inward
tapering form on its radial inner zone 235. It will be apparent that this
tapering form corresponds to the associated form of inner flange 218 as
according to FIG. 25A.

[0221] Owing to this tapering form more space is available in the central
area for accommodating flanges 218 than would be the case if inner
flanges 218 had a uniform width.

[0222] It is duly noted that flanges 218, 219 are welded fixedly to blades
217. If desired, the material thicknesses of blades 217 and of flanges
218, 219 could differ from each other. This is not possible with the
above described exemplary embodiments according to FIGS. 19, 20 and 21.

[0223] The rotation device according to the invention as discussed above
can for instance be embodied as a pump driven by an electric motor,
wherein the pump and the electric motor are assembled into a single unit.
The rotation device according to the invention can also be embodied as a
hydromotor or turbine which is for instance assembled with an electric
generator for converting medium flow energy into electrical energy
supplied by the generator.

[0224] The use of labyrinth seals is referred to in the above
specification. Labyrinth seals are practical and reasonably inexpensive
to produce, but have the drawback of not sealing to sufficient extent
under all conditions. It is thus possible for instance for the liquid
flowing through a rotor and stator to enter a motor or electric generator
due to leakage, which may be undesirable. In such a case use could for
instance be made of single or multiple mechanical seals, which can for
instance be embodied as complementarily modelled sealing rings of for
instance ceramic material pressing against each other and sliding
sealingly over each other. It will be apparent that, as a result of
friction, such seals will undergo a temperature increase and must
therefore be cooled. This drawback is compensated by the fact that such a
rotating seal can seal hermetically.

[0225] Another alternative seal is a so-called brush seal, comprising a
ring of relatively hard bristles generally consisting of metal and having
a usually rounded free top. The ends of these bristles are in sliding
contact with a very hard and wear-resistant opposite layer of for
instance silicon nitride or silicon carbide, or other appropriate, very
hard material. Although the sealing of such brush seals is not fully
hermetic, as in the described case of for instance ceramic discs pressed
against each other, a brush seal nevertheless displays leakage which is
about four times less than a corresponding labyrinth seal. The advantage
of a brush seal is further that the dimensioning tolerance of the
components sealing against each other is considerably greater than in the
case of labyrinth seals, which only allow a very small dimensioning
tolerance. It is noted that in a brush seal the sealing bristles are
oriented trailing at an angle of about 45° relative to the local
direction of displacement, so the relative direction of rotation.

[0226] Further discussed in the specification is the possibility of using
conical screw couplings. Such conical screw couplings are highly
practical in the context of the present invention because they enable a
"blind" fitting, wherein the two screw components are mutually
self-locating. The use of one or more conical screw couplings thus
enables a high measure of compactness and integration of an electric
motor and a rotor, or a rotor and an electric generator.